VNC slow or lots of disconnects

We run VNC 4.0 on our WAN, and I connect to remote machines (500 miles away) through VPN and VNC. On some servers on our network, my vnc performance is just fine. It's tolerably fast and no disconnects. On other servers on the same network, it's either extremely slow, or drops my connection very frequently.

1- Is there a way I can troubleshoot this? If I could tell my sysadmin WHY this is happening, I'm sure he could fix it, but he has better things to do than spend all day troubleshooting vnc connectivity problems.

2- Is there a better/faster/more robust tool than VNC?

3- Any idea why some servers (one in particular), would be dropping my connection, on average, twice per minute?

1) If anything, you should probably do a traffic analysis of your network. So use a tool like Ethereal (http://www.ethereal.com) or PRTG (http://www.paessler.com/prtg) to capture packets and analysis traffic. If something like VNC of all things is having problems, chances are that something else is as well. You'd have to have access to a monitor port on the switch or else your analysis might not turn out so good. Network person might be needed for this if you're not him/her.

2) Remote Desktop if you're running Windows Server 2003.

3) See #1. Might be storm of traffic hitting certain servers or a bad link along the way. Traffic analysis would be the way to initially check... then start looking for other issues.

I like remote desktop because of the speed, but I don't like the layered connection thing. Is there a way to configure RD so that it puts you on "the terminal", like vnc does, rather than running in a background process?